The present invention relates to a real image type finder for a camera.
A real image type finder has been widely employed, for example, in single lens reflex cameras. In the real image type finder, an image of an object is formed on a focusing glass by an imaging optical system, and the image is observed through an eyepiece optical system in a magnified fashion. In such a structure, if foreign particles such as dust particles are adhered to the focusing glass, the foreign particles may be made conspicuous in an image observed through the eyepiece optical system.
Therefore, the real image type finder is assembled generally with maximum caution not to permit the foreign particles adhering to the focusing glass surface. However, when foreign particles are found adhered to the focusing glass surface after the conventional finder is assembled, the finder system must be disassembled for removing the particles on the focusing glass, which results in costing much time and expense.
It is therefore an object of the invention to provide an improved finder system for a camera, in which foreign particles adhered to a focusing glass can easily be removed even after the finder system is assembled.
For the above object, according to the Invention, there is provided a real image type finder for a camera, which is provided with an imaging optical system, a focusing glass disposed at a focusing plane of the imaging optical system, an observing optical system through which the image formed on the focusing glass is observable, a case that accommodates at least the focusing glass and the observing optical system, the case having an opening through which only the focusing glass is allowed to be inserted in/withdrawn from the case, and a covering member that removably covers the opening.
Since the focusing glass can be inserted/withdrawn through the opening formed on the case, foreign particles adhered to the focusing glass can be removed easily, without disassembling the finder.
Optionally, the camera may be a single lens reflex camera having a photographing lens, and the photographing lens may constitute the imaging optical system.
In a particular case, the camera may employ a beam splitter for dividing light passed through the photographing lens into light for photographing, and light that forms the image on the focusing glass. Alternatively, the camera may be one employing a quick return mirror instead of the beam splitter.
Optionally, the covering member may include a covering element, and a sealing element located between the covering element and the focusing glass, and the sealing element may be inserted in the opening.
The sealing element may be a single member formed of elastic material. Further, the sealing element may hermetically seal the opening and hermetically contact the covering element and the focusing glass.
Still optionally, the focusing glass and the sealing element may have respective engaging portions. In this case, the sealing element and the focusing glass may be inserted in/withdrawn from the case through the opening with the respective engaging portions being engaged with each other.
According to another aspect of the invention, there is provided a real image type finder for a camera, that is provided with an imaging optical system that forms an image of an object on a focusing plane, a focusing glass disposed at the focusing plane, an observing optical system, the image formed on the focusing glass being observed through the observing optical system, a case that contains at least the focusing glass and the observing optical system, one side of the case being formed with a first opening that allows at least the beam splitter and the focusing glass to be placed in the case, another side of the case being formed with a second opening, the second opening allowing only the focusing glass to be inserted in and/or withdrawn from the case, a first covering member that covers the first opening, the first covering member being removable from the case, and a second covering member that covers the second opening, the second covering member being removable from the case.
Optionally, the camera may be a single lens reflex camera having a photographing lens, and in this case, the photographing lens may constitute the imaging optical system.
Further, the camera may employ a beam splitter for dividing light passed through the photographing lens into light for photographing, and light that forms the image on the focusing glass.
Still optionally, the second covering member may have a covering element, and a sealing element located between the covering element and the focusing glass, the sealing element being inserted in the second opening.
In this case. the sealing element that may be an elastic element hermetically seals the second opening, and hermetically contacts the covering element and the focusing glass.
Further optionally, the focusing glass and the sealing element have respective engaging portions, the sealing element and the focusing glass being inserted in/withdrawn from the case through the second opening with the respective engaging portions being engaged with each other.